Fault arc detection circuit and electronic device

Abstract

The present invention discloses a faulty arc detection circuit and an electronic device. The faulty arc detection circuit includes an arc sampling circuit, a frequency sweeping circuit and a fault determination circuit; the input end of the arc sampling circuit is connected to the live wire or the neutral wire, the output ends of the arc sampling circuit and the frequency sweeping circuit are both connected to the input end of the fault determination circuit, and the output end of the fault determination circuit is connected to the input end of the frequency sweeping circuit; the arc sampling circuit samples the arc to obtain an arc signal; the fault determination circuit sends different voltage signals to the frequency sweeping circuit through its output end, and the frequency sweeping circuit outputs corresponding different local oscillator signals to the input end of the fault determination circuit according to different voltage signals; the fault determination circuit performs frequency mixing on the arc signal and each local oscillator signal and then conducts fault determination. Since the fault determination circuit uses the signal after frequency mixing the arc signal and multiple local oscillator signals as the basis for fault determination, signal loss is avoided and the detection accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the field of electronic technologies, and particularly to a fault arc detection circuit and an electronic device. Background Art

[0002] An arc is a gas ionization discharge phenomenon, which has characteristics such as high temperature, small current, and short duration. Arcs on a line can be divided into two types, one is a normal operating arc, and the other is a fault arc. When a fault arc occurs, its central temperature can reach 3000°C to 4000°C, and there is also splashing of molten metal. The high temperature and heat generated by the fault arc can easily ignite the line insulation layer, leading to line fires and then causing fires.

[0003] Currently, the solution for detecting a fault arc is as follows: after obtaining an arc signal, the arc signal is input into a resonant amplification circuit, and the signal in the arc signal that is the same as the resonant frequency of the resonant amplification circuit will be output, and a fault determination is made on the output signal. In this solution, the signal that the resonant amplification circuit can output is single, which easily causes the loss of the arc signal, thereby affecting the accuracy of detection.

[0004] The above content is only used to assist in understanding the technical solution of the present invention, and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of the present invention is to provide a fault arc detection circuit and an electronic device, aiming to solve the technical problem of low detection accuracy of fault arcs in the prior art.

[0006] To achieve the above objective, the present invention provides a fault arc detection circuit. The circuit includes an arc sampling circuit, a frequency sweeping circuit, and a fault determination circuit; the input end of the arc sampling circuit is connected to a live wire or a neutral wire, the output end of the arc sampling circuit and the output end of the frequency sweeping circuit are both connected to the input end of the fault determination circuit, and the output end of the fault determination circuit is connected to the input end of the frequency sweeping circuit; wherein,

[0007] The arc sampling circuit is configured to sample the arc of the live wire or the neutral wire, obtain an arc signal, and send the arc signal to the fault determination circuit;

[0008] The fault determination circuit is configured to send different voltage signals to the frequency sweeping circuit through the output end of the fault determination circuit, so that the frequency sweeping circuit outputs different local oscillator signals corresponding to the input end of the fault determination circuit according to the different voltage signals;

[0009] The fault determination circuit is further configured to mix each local oscillator signal with the arc signal after receiving the arc signal and each local oscillator signal to obtain a mixed signal, and perform fault determination based on the mixed signal.

[0010] Preferably, the arc sampling circuit includes a Rogowski coil, the Rogowski coil penetrates through the live wire or the neutral wire, and an output end of the Rogowski coil is connected to an input end of the fault determination circuit.

[0011] Preferably, the frequency sweeping circuit includes a feedback unit and a frequency selection unit; a first end of the feedback unit is respectively connected to a first end of the frequency selection unit and an input end of the fault determination circuit, a second end of the feedback unit is connected to a second end of the frequency selection unit, and a third end of the frequency selection unit is connected to an output end of the fault determination circuit.

[0012] Preferably, the feedback unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first triode, and a first capacitor; wherein,

[0013] A first end of the first resistor is connected to a power supply, and a second end of the first resistor is respectively connected to a first end of the first capacitor, a first end of the second resistor, and a base of the first triode;

[0014] A first end of the third resistor is connected to the power supply, and a second end of the third resistor is respectively connected to a collector of the first triode, an input end of the fault determination circuit, and a first end of the frequency selection unit;

[0015] An emitter of the first triode is respectively connected to a second end of the frequency selection unit and a first end of the fourth resistor;

[0016] A second end of the fourth resistor, a second end of the second resistor, and a second end of the first capacitor are all grounded.

[0017] Preferably, the frequency selection unit includes a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, and an inductor; the fourth capacitor is a varactor diode; wherein,

[0018] A first end of the second capacitor is respectively connected to a collector of the first triode, an input end of the fault determination circuit, and a first end of the fourth capacitor, and a second end of the second capacitor is respectively connected to a first end of the third capacitor and an emitter of the first triode;

[0019] The first end of the fourth capacitor is further connected to an output end of the fault determination circuit, and a second end of the fourth capacitor is respectively connected to a first end of the inductor and a first end of the fifth capacitor;

[0020] The second terminal of the third capacitor, the second terminal of the inductor, and the second terminal of the fifth capacitor are all grounded.

[0021] Preferably, the feedback unit further includes a sixth capacitor. The first terminal of the sixth capacitor is connected to the collector of the first triode, and the second terminal of the sixth capacitor is respectively connected to the first terminal of the second capacitor and the input terminal of the fault determination circuit.

[0022] Preferably, the fault determination circuit includes a mixer, a filtering unit, an amplifying unit, a comparator, and a controller. The input terminal of the mixer is respectively connected to the output terminal of the arc sampling circuit and the output terminal of the frequency sweeping circuit. The output terminal of the mixer is sequentially connected to the controller through the filtering unit, the amplifying unit, and the comparator. Among them,

[0023] The mixer is configured to receive the arc signal and each local oscillator signal, mix the arc signal and each local oscillator signal, and send the obtained mixed signal to the filtering unit;

[0024] The filtering unit is configured to filter the mixed signal, and send the filtered signal to the amplifying unit after obtaining it;

[0025] The amplifying unit is configured to amplify the filtered signal, and send the amplified signal to the comparator after obtaining it;

[0026] When the value corresponding to the amplified signal is greater than the first preset threshold, the comparator outputs a high level to the controller, so that the controller performs fault determination according to the high level.

[0027] Preferably, the filtering unit is further configured to retain the signal with a preset frequency in the mixed signal. Among them, the preset frequency is set according to the difference frequency value between the arc signal and each local oscillator signal.

[0028] Preferably, the controller includes a counter or an analog-to-digital conversion interface. The comparator is connected to the counter or the analog-to-digital conversion interface. The controller is further configured to output an alarm signal when it detects that the number of high levels received by the counter or the analog-to-digital conversion interface within a preset time reaches a second preset threshold.

[0029] The present invention also proposes an electronic device, and the electronic device includes the fault arc detection circuit as described above.

[0030] The present invention is achieved by arranging an arc sampling circuit, a frequency sweeping circuit, and a fault determination circuit in a fault arc detection circuit; the input end of the arc sampling circuit is connected to the live wire or the neutral wire, the output ends of the arc sampling circuit and the frequency sweeping circuit are both connected to the input end of the fault determination circuit, and the output end of the fault determination circuit is connected to the input end of the frequency sweeping circuit; the arc sampling circuit samples the arc on the live wire or the neutral wire to obtain an arc signal and sends the arc signal to the fault determination circuit; the fault determination circuit sends different voltage signals to the frequency sweeping circuit through the output end of the fault determination circuit, so that the frequency sweeping circuit outputs corresponding different local oscillator signals to the input end of the fault determination circuit according to different voltage signals; after receiving the arc signal and each local oscillator signal, the fault determination circuit mixes each local oscillator signal with the arc signal to obtain a mixed signal and performs fault determination based on the mixed signal. Among them, since the fault determination circuit can use the mixed signal formed by the arc signal and a variety of different local oscillator signals as the basis for fault determination, the missing of signals is avoided and the detection accuracy is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0032] Figure 1 is a functional module diagram of an embodiment of the fault arc detection circuit of the present invention;

[0033] Figure 2 is Figure 1 a schematic structural diagram of an optional fault arc detection circuit.

[0034] Description of the reference numerals in the drawings:

[0035] Label Name Label Name 100 Arc sampling circuit N Neutral line 200 Frequency sweeping circuit L Live wire 300 Fault determination circuit KM1 Rogowski coil 210 Feedback unit VCC Power supply 220 Frequency selection unit R1~R4 First resistor to fourth resistor 310 Mixer C1~C6 First capacitor to sixth capacitor 320 Filtering unit L1 Inductor 330 Amplification unit Q1 First triode 340 Comparator MCU Controller

[0036] The realization, functional features, and advantages of the object of the present invention will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0038] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, then such directional indications are only used to explain the relative positional relationship, movement conditions, etc. between components in a certain specific posture (as shown in the drawings). If this specific posture changes, then the directional indications will also change accordingly.

[0039] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, then such descriptions of "first", "second", etc. are only for descriptive purposes and should not be understood as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0040] The present invention provides a fault arc detection circuit.

[0041] Referring to Figure 1 , in one embodiment, the circuit includes an arc sampling circuit 100, a frequency sweeping circuit 200, and a fault determination circuit 300; the input end of the arc sampling circuit 100 is connected to the live wire L or the neutral wire N, the output ends of the arc sampling circuit 100 and the frequency sweeping circuit 200 are both connected to the input end of the fault determination circuit 300, and the output end of the fault determination circuit 300 is connected to the input end of the frequency sweeping circuit 200; wherein, the arc sampling circuit 100 is used to sample the arc of the live wire L or the neutral wire N to obtain an arc signal and send the arc signal to the fault determination circuit 300; the fault determination circuit 300 is used to send different voltage signals to the frequency sweeping circuit 200 through the output end of the fault determination circuit 300, so that the frequency sweeping circuit 200 outputs corresponding different local oscillator signals to the input end of the fault determination circuit 300 according to the different voltage signals; the fault determination circuit 300 is further used to mix the local oscillator signals with the arc signal after receiving the arc signal and each local oscillator signal to obtain a mixed signal and perform fault determination according to the mixed signal.

[0042] It should be noted that in the prior art, the arc signal is usually input into the resonant amplification circuit, and only the signal with the same resonant frequency as the resonant amplification circuit will be output for fault determination. As a result, only a very small number of signals in the arc signal are detected, affecting the accuracy of detection. In the present application, different voltage signals are output from the output end of the fault determination circuit 300 to the frequency sweeping circuit 200, and the frequency sweeping circuit 200 correspondingly generates signals with different frequencies as local oscillator signals. When the arc signal is mixed with each local oscillator signal, more signals will be output for fault determination, effectively improving the comprehensiveness and accuracy of detection.

[0043] It can be understood that the arc sampling circuit 100 samples the arc of the live wire L or the neutral wire N. The coil method can be adopted, such as passing the CT power-taking coil or the Rogowski coil KM1 through the live wire L or the neutral wire N, and connecting the output end of the CT power-taking coil or the Rogowski coil KM1 to the input end of the fault determination circuit 300, so that the sampled arc signal can be transmitted to the input end of the fault determination circuit 300.

[0044] In a specific implementation, after the fault determination circuit 300 mixes the arc signal and each local oscillator signal with different frequencies, the obtained mixed signal includes the original arc signal, the local oscillator signal, the difference frequency signal, the sum frequency signal, etc. After processing the mixed signal through filtering, amplification, comparison, etc., it is determined whether there is a fault arc according to the preset determination conditions.

[0045] In this embodiment, the arc sampling circuit 100, the frequency sweeping circuit 200, and the fault determination circuit 300 are provided in the fault arc detection circuit; the input end of the arc sampling circuit 100 is connected to the live wire L or the neutral wire N, the output end of the arc sampling circuit 100 and the output end of the frequency sweeping circuit 200 are both connected to the input end of the fault determination circuit 300, and the output end of the fault determination circuit 300 is connected to the input end of the frequency sweeping circuit 200; the arc sampling circuit 100 samples the arc of the live wire L or the neutral wire N to obtain an arc signal and sends the arc signal to the fault determination circuit 300; the fault determination circuit 300 sends different voltage signals to the frequency sweeping circuit 200 through the output end of the fault determination circuit 300, so that the frequency sweeping circuit 200 correspondingly outputs different local oscillator signals to the input end of the fault determination circuit 300 according to different voltage signals; after receiving the arc signal and each local oscillator signal, the fault determination circuit 300 mixes each local oscillator signal with the arc signal to obtain a mixed signal and performs fault determination according to the mixed signal. Among them, since the fault determination circuit 300 can use the mixed signal formed by the arc signal and a variety of different local oscillator signals as the basis for fault determination, the missing of signals is avoided and the accuracy of detection is improved.

[0046] Please refer to Figure 1 and Figure 2 , Figure 2 isFigure 1 Optional structural schematic diagram of a fault arc detection circuit 1.

[0047] In this embodiment, the frequency sweeping circuit 200 includes a feedback unit 210 and a frequency selection unit 220; the first end of the feedback unit 210 is respectively connected to the first end of the frequency selection unit 220 and the input end of the fault determination circuit 300, the second end of the feedback unit 210 is connected to the second end of the frequency selection unit 220, and the third end of the frequency selection unit 220 is connected to the output end of the fault determination circuit 300.

[0048] It can be understood that the frequency selection unit 220 receives different voltage signals output from the output end of the fault determination circuit 300, feeds back signals of different frequencies to the feedback unit 210, and the feedback unit 210 amplifies the signals and correspondingly outputs different local oscillator signals.

[0049] Further, the feedback unit 210 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first triode Q1, and a first capacitor C1; wherein, the first end of the first resistor R1 is connected to the power supply VCC, the second end of the first resistor R1 is respectively connected to the first end of the first capacitor C1, the first end of the second resistor R2, and the base of the first triode Q1; the first end of the third resistor R3 is connected to the power supply VCC, the second end of the third resistor R3 is respectively connected to the collector of the first triode Q1, the input end of the fault determination circuit 300, and the first end of the frequency selection unit 220; the emitter of the first triode Q1 is respectively connected to the second end of the frequency selection unit 220 and the first end of the fourth resistor R4; the second end of the fourth resistor R4, the second end of the second resistor R2, and the second end of the first capacitor C1 are all grounded.

[0050] It should be understood that the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 are static operating resistors for setting the static operating point of the triode, and the first capacitor C1 is a decoupling capacitor for removing the influence of noise on the first triode Q1.

[0051] Further, the frequency selection unit 220 includes a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and an inductor L1; the fourth capacitor C4 is a varactor diode; wherein, a first end of the second capacitor C2 is respectively connected to a collector of the first triode, an input end of the fault determination circuit 300, and a first end of the fourth capacitor C4, and a second end of the second capacitor C2 is respectively connected to a first end of the third capacitor C3 and an emitter of the first triode Q1; the first end of the fourth capacitor C4 is further connected to an output end of the fault determination circuit 300, and a second end of the fourth capacitor C4 is respectively connected to a first end of the inductor L1 and a first end of the fifth capacitor C5; a second end of the third capacitor C3, a second end of the inductor L1, and a second end of the fifth capacitor C5 are all grounded.

[0052] It should be understood that the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all resonant capacitors, the inductor L1 is a resonant inductor, and the resonant frequency of the frequency sweeping circuit 200 (i.e., the frequency of the local oscillator signal) is where C X is the total equivalent capacitance in the scanning circuit, approximately equal to the sum of the fourth capacitor C4 and the fifth capacitor C5.

[0053] It should be noted that the fourth capacitor C4 is a varactor diode. A varactor diode belongs to a reverse-biased diode. By changing the reverse bias voltage on its PN junction, the capacitance of the PN junction can be changed. The higher the reverse bias voltage, the smaller the junction capacitance. The relationship between the reverse bias voltage and the junction capacitance is non-linear. A voltage signal u x is applied across the two ends of the fourth capacitor C4 through the digital-to-analog conversion interface DAC of the controller MCU. x The capacitance value of the fourth capacitor C4 changes with the change of u

[0054] The resonant frequency of the frequency sweeping circuit 200 also changes with the change of the capacitance value of the fourth capacitor C4. At different times, different resonant signals are output as the local oscillator signals of the mixing device in the fault determination circuit 300, realizing the function of frequency sweeping.

[0055] It should be understood that the sixth capacitor C6 is an output coupling capacitor for coupling and outputting the local oscillator signal.

[0056] Further, the fault determination circuit 300 includes a mixer 310, a filtering unit 320, an amplifying unit 330, a comparator 340, and a controller MCU. The input end of the mixer 310 is respectively connected to the output end of the arc sampling circuit 100 and the output end of the frequency sweeping circuit 200. The output end of the mixer 310 is sequentially connected to the controller MCU through the filtering unit 320, the amplifying unit 330, and the comparator 340. Among them, the mixer 310 is configured to receive the arc signal and each local oscillator signal, mix the arc signal and each local oscillator signal, and send the obtained mixed signal to the filtering unit 320. The filtering unit 320 is configured to filter the mixed signal to obtain a filtered signal and send it to the amplifying unit 330. The amplifying unit 330 is configured to amplify the filtered signal to obtain an amplified signal and send it to the comparator 340. The comparator 340 is configured to output a high level to the controller MCU when the value corresponding to the amplified signal is greater than a first preset threshold, so that the controller MCU performs a fault determination based on the high level.

[0057] It should be understood that the mixer 310 mixes the arc signal with a variety of local oscillator signals generated by the frequency sweeping circuit 200. The output mixed signal includes the original arc signal, the local oscillator signal, the difference frequency signal, the sum frequency signal, etc. In this embodiment, the model of the mixer 310 is not limited.

[0058] The filtering unit 320 filters the mixed signal to filter out signals that do not meet the requirements. Specifically, the filtering unit 320 can retain the signal with a frequency of a preset frequency in the mixed signal. Among them, the preset frequency is set according to the difference frequency value between the arc signal and each local oscillator signal. For example, it can be set that the filtering unit 320 allows the signal with a difference frequency value of 455 kHz between the arc signal and the local oscillator signal to pass through.

[0059] The comparator 340 sets a first preset threshold and compares the first preset threshold with the value corresponding to the amplified signal. When the first preset threshold is less than or equal to the value corresponding to the amplified signal, the comparator 340 outputs a high level to the controller MCU.

[0060] Further, the controller MCU includes a counter or an analog-to-digital conversion interface AD. The comparator 340 is connected to the counter or the analog-to-digital conversion interface AD. The controller MCU is further configured to output an alarm signal when it detects that the number of high levels received by the counter or the analog-to-digital conversion interface within a preset time reaches a second preset threshold.

[0061] In a specific implementation, the second preset threshold can be set to 14, and the preset time can be set to 1 second. That is, when the controller MCU detects that the number of high-level pulses of its counter or analog-to-digital conversion interface reaches 14 within 1 second, the controller MCU outputs an alarm signal. Of course, the preset time and the second preset threshold can also be set otherwise according to experience, and this embodiment does not limit this.

[0062] In this embodiment, through the specific design of the arc sampling circuit, the frequency sweep circuit, and the fault determination circuit, the arc signal on the line is sampled, and a local oscillator signal of different frequencies is output to the mixer. The mixer mixes the arc signal with the local oscillator signal, the filtering unit filters the mixed signal, and the amplification unit amplifies the filtered signal; the comparator compares the amplified signal with the first preset threshold. When the value corresponding to the amplified signal is greater than the first preset threshold, the comparator outputs a high level to the counter or analog-to-digital conversion interface of the controller, and the controller determines whether there is a fault arc according to the number of high levels within the preset time. Since the mixer in this embodiment can output arc signals in multiple frequency bands, the characteristic quantities of the detected arc signals are enriched, and the detection accuracy is improved.

[0063] The present invention also provides an electronic device, which includes the above-mentioned fault arc detection circuit. The circuit structure of the fault arc detection circuit of the electronic device can refer to the above embodiment and will not be elaborated here; it can be understood that since the electronic device in this embodiment adopts the technical solution of the above-mentioned fault arc detection circuit, the electronic device has all the above beneficial effects.

[0064] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A fault arc detection circuit, characterized in that, It includes an arc sampling circuit, a frequency sweeping circuit and a fault determination circuit; the input end of the arc sampling circuit is connected to the live wire or the neutral wire, the output end of the arc sampling circuit and the output end of the frequency sweeping circuit are both connected to the input end of the fault determination circuit, and the output end of the fault determination circuit is connected to the input end of the frequency sweeping circuit; wherein, The arc sampling circuit is used to sample the arc of the live wire or the neutral wire, obtain an arc signal, and send the arc signal to the fault determination circuit; The fault determination circuit is used to send different voltage signals to the frequency sweeping circuit through the output end of the fault determination circuit, so that the frequency sweeping circuit outputs different local oscillator signals corresponding to the input end of the fault determination circuit according to the different voltage signals; The fault determination circuit is further used to mix the local oscillator signals with the arc signal after receiving the arc signal and each local oscillator signal, obtain a mixed signal, perform signal processing on the mixed signal, and perform fault determination according to the mixed signal after signal processing and a preset determination condition; The arc sampling circuit includes a Rogowski coil, the Rogowski coil penetrates through the live wire or the neutral wire, and the output end of the Rogowski coil is connected to the input end of the fault determination circuit; The frequency sweeping circuit includes a feedback unit and a frequency selection unit; the first end of the feedback unit is respectively connected to the first end of the frequency selection unit and the input end of the fault determination circuit, the second end of the feedback unit is connected to the second end of the frequency selection unit, and the third end of the frequency selection unit is connected to the output end of the fault determination circuit.

2. The fault arc detection circuit according to claim 1, characterized in that The feedback unit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first triode and a first capacitor; wherein, The first end of the first resistor is connected to the power supply, and the second end of the first resistor is respectively connected to the first end of the first capacitor, the first end of the second resistor and the base of the first triode; The first end of the third resistor is connected to the power supply, and the second end of the third resistor is respectively connected to the collector of the first triode, the input end of the fault determination circuit and the first end of the frequency selection unit; The emitter of the first triode is respectively connected to the second end of the frequency selection unit and the first end of the fourth resistor; The second end of the fourth resistor, the second end of the second resistor and the second end of the first capacitor are all grounded.

3. The fault arc detection circuit according to claim 2, wherein, The frequency selection unit includes a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor and an inductor; the fourth capacitor is a varactor diode; wherein, The first end of the second capacitor is respectively connected to the collector of the first triode, the input end of the fault determination circuit and the first end of the fourth capacitor, and the second end of the second capacitor is respectively connected to the first end of the third capacitor and the emitter of the first triode; The first end of the fourth capacitor is further connected to the output end of the fault determination circuit, and the second end of the fourth capacitor is respectively connected to the first end of the inductor and the first end of the fifth capacitor; The second end of the third capacitor, the second end of the inductor and the second end of the fifth capacitor are all grounded.

4. The fault arc detection circuit according to claim 3, wherein, The feedback unit further includes a sixth capacitor. A first end of the sixth capacitor is connected to a collector of the first triode, and a second end of the sixth capacitor is respectively connected to a first end of the second capacitor and an input end of the fault determination circuit.

5. The fault arc detection circuit according to any one of claims 1 to 4, characterized in that, The fault determination circuit includes a mixer, a filtering unit, an amplifying unit, a comparator, and a controller. An input end of the mixer is respectively connected to an output end of the arc sampling circuit and an output end of the frequency sweeping circuit. An output end of the mixer is sequentially connected to the controller through the filtering unit, the amplifying unit, and the comparator. Among them, The mixer is configured to receive the arc signal and each local oscillator signal, mix the arc signal and the local oscillator signals, and send the obtained mixed signal to the filtering unit. The filtering unit is configured to filter the mixed signal, and send the filtered signal to the amplifying unit after obtaining the filtered signal. The amplifying unit is configured to amplify the filtered signal, and send the amplified signal to the comparator after obtaining the amplified signal. The comparator is configured to output a high level to the controller when a value corresponding to the amplified signal is greater than a first preset threshold, so that the controller performs fault determination according to the high level.

6. The fault arc detection circuit according to claim 5, wherein The filtering unit is further configured to retain a signal with a frequency of a preset frequency in the mixed signal. The preset frequency is set according to a difference frequency value between the arc signal and the local oscillator signals.

7. The fault arc detection circuit according to claim 6, wherein The controller includes a counter or an analog-to-digital conversion interface. The comparator is connected to the counter or the analog-to-digital conversion interface. The controller is further configured to output an alarm signal when it is detected that the number of high levels received by the counter or the analog-to-digital conversion interface within a preset time is a second preset threshold.

8. An electronic device, characterized in that, A fault arc detection circuit according to any one of claims 1 to 7 is included.

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